Floor furnace



July 20,1943.

R. MARTIN 2,324,862

" FLOOR FURNACE Filed Feb. 1:, i941 4 Sheets-Sheet l INVENTOR @1356 Mar f/h. I

. ATTOIQNEY July 20, 1943.

FLOOR FURNQCE Filed Feb. 15, 1941 4 Sheets-Sh eet 2 Patented July 20, 1943 FLOOR FURNACE Russell Martin, Wichita, Kans, assignor to The Coleman Lamp and Stove Company, Wichita, Kans., a corporation of Kansas Application February 13, 1941, Serial No. 378,698

. 11 Claims.

This invention relates to furnaces, and more particularly to a type adapted for suspension within a floor opening and commonly known as floor furnacesl Furnaces of this character are'often installed in confined out of way places andv in buildings having no basement, consequently they must be self-contained in an outer jacket or casing, which is completely closed at the sides and bottom and usually without exterior means of access except through the top thereof. Operating adjustment 1 and servicing of such furnaces are difiicult, especially when equipped for burning liquid fuels, since in furnaces as heretofore constructed these operations must be carried on in close spaces under the floor of the building.

Therefore, the principal object of the present invention is to provide'a simple, inexpensive con- 'struction, adapted for operating and servicing through or from above the floor opening.

Other objects of the invention are to provide the furnace with a heater and burner assembly that is completely removable as a unit through the top opening of the outer jacket; to provide a floor furnace particularly adapted for use in connection with liquid fuels; and to provide the floor furnace with a combustion chamber which may have two burners and an intermediate heat exchanger tube arranged so that the products of combustion fromeither burner do not readily mix with those of the other and thereby obtain high thermal eificiency when the burners are operated at different burning rates.

7 Other objects of the invention are to provide fuel and flue connections for the removable unit that may be readily effected within the furnace jacket; to provide a shut-off valve for the fuel which is located within the furnace casing; to provide a stable support for the removable unit within the outer jacket; to provide a fixed mounting of the fuel control valve with respect,

to the level of the burner fire-pots; to provide a levelling adjustment of the fuel control and safety valve on the supporting frame of the re.-

movable unit which is readily manipulated when the removable unit is in operating position; to provide the removable unit with means for 10- to better illustrate the eating and supporting the inner jacket which separates the moving air columns within the furnace; to provide the supporting means with fastening devices'to anchor the removable unit within the casing for shipping purposes; andto provide the furnace with a combination draft regulator and flue connection that-can be readily assembled into the outer casing from'the interior thereof after the casing has been installed. Other objects of the invention are to supply air from within the outer jacket to support combustion and for regulating the draft through the draft regulator; and to provide adraft regulator which responds to difference in pressure inside the burner and the pressure in the furnace casmg.

Further objects are to provide a draft regulator so designed that it may be readily adjusted through the top of the furnace while observing condition of the flame through a peep-hole in the top of the combustion chamber; to provide the outer jacket with a"clean-out door in the bottom thereof which is readily opened and 'closed from the floor level above the furnace;

and to provide the fuel linesleading from the constantlevel control and safety valve to the burner pots with controls having operating stems readily manipulated through the fioor grill and which are supported from the inner jacket and removable therewith.

Other objects of the invention are to provide a combustion chamber .designed for maximum heat exchange between the products of combustion and the air to be heated which is circulated through the furnace; to provide a heating unit having a relatively large heating surface; and to provide the combustion chamber with an updraft air circulating tube located between a pair of .fire-pots to'increase the heating surface and to effect uniformly distributed heat flow, thus preventing excessivehot spots on the floor grill.

In accomplishing these and other objects of the invention, as hereinafter described, I have provided improved structure, the preferred form of which is illustrated in the accompanying drawings, wherein: p

Fig. 1 is a perspective view showing installation of a floor furnace embodying the features of the present invention, a part of the outer and inner jackets and floor grill being broken away construction of the furnace. j

'Fig. 2 is a perspectiveview of the removable heating unit viewed from the flueside thereof.

Fig. 3 is a plan View ofthe furnace,.a palttpf whichis shown in horizontal section.

' Fig. '4 is an enlarged section through the draft regulator on the line 4-1 of. Fig.

i 5 is a detail .view ofthe constant' level control and safety valve moi'mting};parts: being shown i n section to better illustrate the construction thereof.

Fig. 6 is a vertical section through the furnace on the line -6 of Fig. 3.

Fig. '7 is a vertical section taken at right angles to the section shown in Fig. 6, and on the line 1-1 of Fig. 3.

Fig. 8 is a detail view of the clean-out door in the bottom of the outer jacket.

Fig. 9 is a section through the clean-out door on the line 9--9 of Fig. 8.

Fig. 10 is a similar section showing the door in open position. 4

Fig. 11 is a section through the flue connection.

Referring more in detail to the drawings:

I designates a floor furnace constructed in accordance with the present invention, and which includes an outer jacket or casing /2, an inner jacket 3, a burner and heating unit 4, and a floor grill 5. The outer jacket 2 comprises a box-like shell having sheet metal front. and rear walls 6-! connected by side walls B9 and a bottom Hi, the margin of the bottom I!) being curved downwardly and inwardly as indicated at H, and then inclined upwardly to a flat central portion |2. The curvature. of the bottom not only enhances the rigidity thereof but serves to streamline the vflow of down-draft air into an upwardly flowing column and provides a marginal trough to facilitate sweeping of dirt accumulating in the bottom of the furnace toward a clean-out opening l3, normally closed by a door l4.

The door |4- fits closely within the opening and has a marginal flange |5 engaging the under face of the furnace bottom. The door is attached at one end by a hinge l6 so that it swings downwardly when pushed open. The opposite end of the door carries a latch and handle l'l, formed of spring material and having one end l8 attached to the inner face of the door and the other end curved upwardly in the form of a loop H and terminating in a slotted head slidably retainedin engagement with the inner face of the door by a rivet 2|. as shown in Fig. 9, the ear cooperating with the loop in forming a latch to engage with a keeper 22 fixed to the jacket bottom at the end of the clean-out opening. The upper edges of the side walls terminate in laterally extending flanges 23 that are adapted to engage the marginal edges about a floor opening when the furnace is installed, as later described.

Mounted in two adjacent corners of the jacket, and spaced slightly above the bottom, are brackets 24 and 25 cooperating with a single bracket 26 located substantially in the center at the oppositeside of the jacket to support the burner and heating unit 4, later described. The brackets 24 and 25 have bridge portions 21 extending diagonally across the corners and terminating in cars '28 and 29 that are secured to the inner faces of the jacket. The bridge portions of the brackets have inwardly extending lateral flanges 3|! provided with openings 3|for a purpose later described. The bracket 25 has an attaching portion 32 and a laterally extending flange 33 located in a plane parallel with the flanges 33 of the brackets 24 and 25.

at one end thereof, as shown in Fig. 3; The front of the wall 31 has a marginal flange 40, and fixed thereto is a plate 4| having an opening 42 substantially in registry with the flue collar 33 and an opening 43 in the opposite end to accommodate a draft regulator. The draft regulator comprises a frame 44 inset within the opening 43 and forming a seat 45 for a regulator valve 46. The regulator valve is suitably trunnioned at the sides thereof at a point above its hurl zontal diameter so that the regulator valve is out of balance and will swing outwardly at the bottom. The regulator valve is normally urged to closed position by a weight 5| that is attached thereto as shown in Fig. 4. The regulator valve is provided at a point above the. trunnioning axis with an internally threaded insert 48 to mount the threaded shank of a balance adjusting screw 49.

The inner end of the adjusting screw carries a knob 50, and the other end the weight 5| so that by adjusting the relative position of the weight 5| with respect to the regulator valve 46, the regulator valve automatically opens with response to chimney draft to control the draft on the heater and burner unit. The draft regulator valve is thus responsive to'diiferential in pressure within the flue pipe and the air in the furnace casing. Since this air is of fairly uniform room temperature, the draft regulation is better effected in oil burning floor furnaces and there is not such irregular operation as would be the case where the temperature of the air varies widely. The complete draft regulator assembly is inserted through the opening 34 from the interior of the jacket 2 and is secured therein by fastening devices, such as screws 52, extending through suitable openings in the corners of the plate 4| and through registering openings in the wall of the jacket, as shown in Fig. 4. The rear wall I of the jacket has reinforcing ribs 53 attached to and extending vertically of the inner face thereof, and the opposite wall 6 has similar reinforcing ribs 54 which form guides in facilitating insertion of the burner and heating unit, as

later described.

The rear wall 1 of the jacket is provided with a an elongated opening 34 to accommodate a draft regulator assembly 35, the opening preferably having semicircular ends. The draft regulator assembly includes a substantially pan-shaped,'

elongated body 38 having its side wall 31 projecting through the opening 34 and its. back wall 38 carrying a flue pipe connecting collar 4' The inner jacket includes front and rear walls 555|5 and side walls 51-58 spaced inwardly from the corresponding walls 6-! and 8-9 of the outer jacket to provide down-draft air passageways 59. The inner jacket is of suflicient length to extend from substantially the plane of the brackets 24, 25 and 26 to a point spaced below the flanges of the outer jacket where they converge inwardly, as at 60, forming widened throat for the passageways 59. The terminal edges of the walls are flanged inwardly to enhance the rigidity thereof. The walls just described are preferably provided with liners 5 |62 and SH, respectively, of slightly shorter height than the outer walls and supported therefrom by channel-shaped spacers 65 (Fig. 3). The

upper ends of the liners also converge inwardly,

as at 58, but terminate short of the upper ends of the jacket walls so that the effective. outlet opening is substantially the same capacity as that formed by the outer flanges as shown in Fig. 'I. The rear wall 55 and the liner 62 are provided with slotted openings 61 registering with the flue opening and extending through the bottom edges thereof, whereby the inner jacket may be passed over a flue connection as later described. Fixed within the upper end of the slotted opening is a substantially arcuate-shaped hood I to divertthe air moving downwardly in the eway ll cylindrical walls over the sides of the flue connection and to conduct air heated by the flue connection into the heated column of air.

The burner and heating assembly 4 includes a combustion chamber or heating unit 69 formed by a wall sheet rolled to provide parallel front and rearwalls I and it connected by substantially semicircularend wall I2 and 13, spaced from the liners 6I-62 and 63-64, respectively. to provide up-draft passages I4 therebetween. The upper end of the combustion chamber is closed by a top I5, and the lower end by a bottom IS. The top IS has a flange TI sleeved over the upper edges of the combustion chamber walls.

and is provided with a crowned upper portion I8 having openings I9 and 80 at the respective ends thereof and which are provided BI to receive packing 82 for seating lids or doors 83 and 84, the doors being hinged by rods 85 extending through ears on the doors and through ears on brackets 86 attached to the upper face of the top as shown in Fig. 2. The door and handles 81 are located on the sides opposite the e e gins of the doors are shaped to form peripheral flanges overlapping the edge of the bpenings to provide substantially gas-proof joints when the doors are closed.

The combustion chamber bottom I6 is inset within the lower portion 88 of the combustion chamber walls a distance to form a'burner chamber 89\therebelow, and is welded to the walls as indicated at 90 to provide a gas-tight joint therebetween. The burner chamber is closed at the bottom by a plate 9|. The combustion chamber bottom has openings 92 therein located coaxially with the door openings'in the top wall to suspend burner pots 33 and 94. and the bottom plate has coaxial air inlet openings 95 for admitting combustion supporting air to the burner pots. The elongated construction of the combustion chamber not only provides space for a plurality of burner pots. but also provides maximum heat transfer surface for a given size furnace.

with inset flanges trol and safety valve unit I I8.

The burner and heating unit is attached to In order to increase the heat transfer area,

to provide better heat flow distribution throu h the grill, and provide for control of the products of combustion in their movement toward the flue opening, the combustion chamber has an uD- draft air circulating tube 96 located midway between the burner pots andsealed within openines 91 and 98 in the top and bottom plates of the combustion chamber, as best shown in Fig. 7. the lower end of the tube extending through a're istering opening- 99 in the bottom plate 9|. The tube is of a diameter relative to the front and back depth of the combustion chamber that relatively narrow spaces I 00 and IIlI are provided therebetween.

The burner pots 93 and 94 preferably have I02 provided with air inlet openings I03 formed therein at a po nt spaced above the bottom I04. The rims of the po s are provided .with lateral flanges I05, which are secured to the upper surface of the combustion chamber bottom. Supported directly above the first series of air inlet openings I03 is a conical-shaped. low flame ring I01 formin a relatively narrow flame opening I08 to better control combustion of the fuel when the fuel supply is turned relatively low in providing a low heat. The op n tops of the fire-pots are provided with high flame burner rings I09 having flame openings H0. flame rings are supported in posit-ion by pins III extending inwardly from the The low walls of the pots." The high flame burner rings I09 have shouldered peripheries I I2 adapted to seat upon the flanges I05. The fire-pots are provided adjacent the bottom thereof with fuel inlet openings II3 that are connected by'tubes III and H5 with valves H8 and II I, respectively, the valves being positioned in and forming a part of the fuel level conframe H9. The frame II! includes angle-bars I and I2I, arranged parallel with the side walls 8 and 9 of the outer jacket and positioned so that the inner jacket seats thereon, as shown in Fig. 7, the forward end of the bars being connected bya cross-bar I 22 seating the front wall of the inner jacket, as shown in Fig. 6. The bars just described are preferably formed of a single angle-bar, cut and bent to form the corner connections and arranged so that the vertical flanges I22 thereof engage the outer faces of the front and side walls of the inner jacket to space the inner jacket relatively to the outer jacket and maintain fixed width of the passageways 59. The frame also includes-angularly extending bars I23 and I24, having their rear ends welded tothe'rear ends of the bars I20 and I2I and their forward ends secured to the horizontal flanges of the cross-bar I22 as by welding or the like. The free ends of the anglebars are connected by a cross-bar I that is This spaced forwardly of the cross-bar I22. member of the frame is also formed of an angle bar. The cross-bar I25 is of a length so that the junctures thereof with the bars I23 and I24 engage the ribs 54, whereby the frame is guided 2 into position within the outer jacket when it is insertedtherein. The frame just described is secured to the bottom of the burner and heating unit by welding or suitable fastening devices.

When the supporting frame, including the heater and burnerunit, is in position in the outer jacket, the rear ends of the angle-bars seat upon the flanges of the brackets 24 and 25, and the vertical flange of the cross-bar I25 seats on the flange 33 of the bracket 26. The brackets thus provide a three-point support for the frame so that it is retained in stable position regardless less of any inclination occurring in the frame.

This is effected by means of a plate I28 posi tioned between the cross-bars I22 .and I25 (see Figs. 5 and 6) The forward end of the plate is provided with spaced openings I29 and I30 which pass the shanks of screws I3I and .I32 which are loosely projected through openings I33 and I34 in the flangesof the cross-bar I22 and are susv pended therein by the heads I35 thereof engaging the upper face of the flange. I28 is supported by nuts I36 attached thereto, and urged away from the anglebar I22 by means of coil springs I31 having their ends bearing against the flange of the cross-bar and plate, respectively, as shown in Fig. 5. The opposite edge of the plate is provided with a vertical flange I38, having an opening I39 engaging a The plate outer j trunnion I48 projecting from the inner face of the vertical flange of the front cross-bar I25. The plate is thus adapted'to pivot on the trunnion in all directions by adjusting the fastening devices I3I and I32 so that the nuts I38 on the shanks thereof support the plate in level position.

The fuel level control and safety valve may be of any approved construction, and is provided; with the valves H and II! which are incorporated therein and adapted to be operated by meansof stems MI and I42. The lower ends of the stems are releasably engaged with the valves, while the upper ends are journalled in an arm I43 of a bracket I44 attached to the upper portion of the front wall of .the inner jacket, as

Whenthe furnace is to be installed, an opening is made in the floor of the building and the' floor joists are connected by suitable headers 'as' in conventional" ade from a chimney to the point of connection with the furnace, and the fuel line I52 is installed from the source-of supply. The outer jacket is then passed through the floor opening so that it is supported by the flanges 23 and secured to the best shown in Fig. 6. The stems are yieldingly springs I45 engaging the arm of the bracket and washers I46 supported on the stems by cotter pins I41. The upper ends of the stems are bent laterally, as at I48, so that they may be selectively engaged by means of a key (not shown) projectable through openings in the grill.

Supported adjacent the end wall of the outer jacket, on the inner side thereof, is a shut-off valve I58, which is held-in stable position by an arm I5-L attached to the front wall 8 of the acket-as shown in Fig. 3. The fuel supply line I52 (Fig. 3) extending through a suitable opening in the outer jacket is connected to the inlet of the valve, and the outlet of the valveis connected by a union nut I53 with a tube I54, having its opposite end connected with the inlet, I55 of, the constant level ,control and-safetyvalve as shown in Fig. 3. Y The rear wall of the combustion chamber has an opening I51 registering with the flue opening 42 of the draft regulator assembly, and fixed within the opening I51 is a collar I58 having a groove in one side thereof. Slidable within the flue opening is a thimble I88 adapted to be spaced from the terminal edge of the collar I58, and which is adapted to abut retained in engagement with the valves by coil lower end thereof seats uponthe angle-bars of a bead I5I in a clamping band I62 that is fixed thereto. The clamping band I62 is sleeved over the collar I58, and the terminal ends thereof are provided with ears I83 and I64 adapted to be drawn together to close the band about the collar and thimble by fastening devices, such as bolts I85. When the band is in position, a bead I68 therein engages in the groove of the collar to space the thimble from the collar and retain the thimble in position relatively to the opening 42."

To enhance the radiating surfaces ofthe combustion chamber, the exterior thereof may be provided with a plurality of vertically arranged fins I61. Each of the fins has a footing flange I88 welded to the wall of the combustion chamber and a hook-shaped reinforcing flange I88 on the opposite-edge as shown in Fig. 2. The fins may also be provided with transverse slots I18.

The floor grill '5 may be of any approved construction, having sufiicient strength to support the weight of persons standing upon the grill, or walking thereacross.

When the furnace is prepared for shipping, bolts are extended through openings in the ends of the bars I23and I24, and throughthe openings 3| in theflanges 38 of the brackets. Two bolts are also put through the front of the furnace into the bracket, so that the removable unit is securely anchored within the outer jacket. These bolts, however, are removed and discarded when the furnace is uncrated.

edge surrounding the floor opening. The draft regulator and flue connection unit 35 is then passed through the open top of the jacket and projected through the opening 34 so that the collar 39 thereon connects with the flue pipe and the flange 48 thereof abuts against the inner face of the jacket. The draft regulator is then secured in position by the fastening devices 52. The supply pipe I52 is connected to the valve I58. The thimble I68, carrying the loosened clamping band I62, is pushed back into the opening 42. The heating and burner unit assembly, which includes the supporting frame H9 with the fuel level control and safety valve mounted thereon, is passed through the open top of the outer jacket and lowered thereinto, with the rear of the sup porting frame guided by the corners of the jacket and the front by the ribs 54, until the supporting frame seats upon the brackets 24, 25 and 26. The fuel control and safety valve unit may then be adjusted to level position by rotating the screws I53. The clamping band is then slid over the collar I58 so that the rib therein engages in the groove of the collar, whereupon the fastening devices are tightened to secure the band about the collar I58. The inner jacket carrying the valve stems is then moved into position so that the the supporting frame, the notch in the rear wall of the jacket accommodating the flue connection. The valve stems are then connected with the control valves. 7

The fuel may then be turned on tive fire-pots by opening the stop valve I58 and opening the regulating valvesv I I6 and M1 to low setting. When the valves are thus opened, fuel will flow into the fire-pots. The fuel is lighted through the door openings in the top of heater, after which the doors are closed. As the fire-pots heat up thefuel valves H6 and H1 may be gradually opened to full setting. The draft regulator is then adjusted by the knob 58 to obtain a desired flame color. This may be noted through suitable peep openings in the top of the heating chamber. The grill is then applied over the open top of the furnace, completing the installation.

The products of combustion rising from the fire-pots travel upwardly to the combustion chamber top, then downwardly over the combustion chamber and draft tube walls to theflue opening. As the combustion chamber walls are heated, air circulation occurs through the floor grill, the hot air rising in the space around the combustion chamber and being discharged through the central portion of the grill, which air is replaced by cooler air passing downwardly through the marginal portions of'the' grill and through the down-draft passages 59, under the lower edge of the inner jacket, and then. upwardly in heat exchange relation with the heating surfaces.

Since the constant level control and safety valve unit is located within the outer jacket and practice. Flue connections may-beto the respecthe adjusting the position of the weight on the regulator valve.

After the furnace has been in use and servicing becomes necessary, the floor grill is removed, followed by the inner jacket. The union I53 is then disconnected from the shut-off valve and the clamping band I62 is loosened to slide the thimble I60 retractively into the opening 42. V The heater and burner unit is then removed so that the entire servicing operations may be carried on above the floor level. Dirt, and the like, may accumulatein the outer jacket, and this may be readily removed through the clean-out opening in the bottom of the outer jacket upon opening of the door M. This is effected by pushing'against the door with a suitable rod to release the latch, whereupon the door drops away from the opening. The dirtand dust may then be swept into the trough-like margin of the jacket, bottom and moved out through the clean-out opening l3. The dooris closed by engaging the loop-shaped handle thereof with a hooked end of the rodand pulling on the rod to latch the door. After servicing of the burners and metering valves has been completed, the heating unit assembly is again installed in the furnace. The clamping band of the flue connection is then retightened and the pipe I54 is connected with a shut-off valve. When the stop valve is opened, fuel supply is again established to the control valves; The inner jacket is then inserted and the actuating stems MI and I42 are connected with the control valves. The grill is then replaced, thus restoring the furnace to operative condition.

It is thus obvious that all of the regulating and maintenance operations are carried on from within the inside of the outer jacket, or above thefloor level of the room, and that the parts requiring service are readily removed as a complete unit assembly, thereby simplifying servicing and cleaning of the furnace.

What I claim and Patent is:

1. A floor furnace including, a j'ackethavi-ng a flue connection, a heating unit comprising a burner andcombustion chamber positioned in the jacket and removable through th top thereof, an outlet collar fixed to the combus-tionchamber,

desire to secure by Letters burner assembly including a supporting frame, a constant .level control valve for supplying fuel to the burner of said assembly, and means for mounting the constant level control valve on the frame I including a plate-lik member having trunnioned support on the frame at one side of said plate-like member andlevelling support on the opposite side.

4. In a liquid fuel burning floor furnace, a

casing having an open top, a combustion chamber, burner and constant level fuel control valve assembly having removable support in the casing whereby said assembly is removable as a unit through the open top of the casing, a fuel supply duct extending into the casing, and coupling means connecting said duct' with the constant level fuel control valve for disconnecting the supply duct when said assembly is to be removed from the casing.

5. In a liquid fuel burning floor furnace, a casing having an open top, acombustion chamber, burner and constant level fuel control valve assembly having removable support in the casing whereby said assembly is removable as a unit through the open top of the casing, a fuel supply duct extending into the casing, coupling means connecting said duct with the constant level fuel control valve for disconnecting the supply duct when said assembly is to be removed from the casing, and a shut-off valve in the casing ahead of said coupling means for shutting oil the fuel supply upon disconnection of thecoupling means.

6. A furnace of the character described including, a casing, brackets in said casing, a unitary assembly including a combustion chamber, heater, and a burner, a supporting frame carrying the unitary assembly on said brackets, a valve unit in said casing. controlling supply of fuel to the burner of said unitary assembly, and levelling ing, frame supporting means in said casing, a

a contractable band for removably connecting the outlet collar with the flue connection, and a supportingframe carrying said unit and having sup- I port within said jacket.

2. A furnace of the character described including, a jacket having a flue connection, a heater, assembly including a combustion chamber and a burner positioned in the jacket, a supporting frame carrying said assembly and having support within said jacket, a collar on the combustion chamber having coaxial alignment with said frame having removable support on said supporting means, a heating unit comprising a burner, combustoin chamber, and a fuel control valve moval with the frame through the open top of the casing, ing the control valve on the frame and adapted. for levelling said valve on the frame.

e 8. A floor furnace including, an open top casing, frame supporting means in said casing, a frame having removable support on said supporting means, a heating unit comprising a burner, combustion chamber, and a constant level all carried by the frame for insertion and refuel control valve all carried by the frame for insertion and removal with the frame through said open top of the casing, levelling means.

mounting said constant level valve on the frame,

. a jacket seat on the frame, and a jacket insertflue connection, an inner jacket around said assembly and supported by said supporting frame,

said inner jacket'having a notch-like opening passing the flue connection, and a contractable band connecting the collar with the flue connec- 'tion.

3. In a floor furnace, a removable heater and able through the open top of the casing to surround the heating unit'and form downdraft and updraft passageways, said constant level valve being located on said frame within the downdraft passageway.

9. A floor furnace including, an opentop casing, frame supporting means in said casing, a frame having removable support on said supporting means, a heating unit comprising a ,burner, combustion chamber, and a constant level fuel control valve all carried by the frame and insertable through the open top of the casing with the frame and removable with the frame through said open top of the casing, means mounting the and an adjustable mounting attachconstant level valve on the frame, a Jacket seat on the frame, a Jacket insertable through the open top of the casing to surround the heating unit and form downdraft and updraft air pas-- prising a burner and combustion chamber, a flue connection on the casing, an outlet collar fixed to the combustion chamber in registering alignment with the flue connection, and a clamp member removably connecting said collar with the flue connection, said heating unit assembly being removable through the open top of the casing upon disconnection of said clamp member.

11. A floor furnace including, an open top casing for support within a floor opening, a unit assembly including a burner, a combustion chamber and a. constant level fuel metering valve, venting means extending through a wall of the casing and having connection with the combustion chamber, fuel supply means extending through a wall of the casing and connected with the constant level fuel metering valve, and coupling means in both the venting means and the fuel supply means accessible through the'open top of the casing for disconnection to permit removal of said unit, assembly through the open top of the casing. RUSSELL MARTIN. 

